Quickly adjustable vise jaw with tool couple elements

ABSTRACT

A multiple purpose workholder of the relatively movable jawtype, especially adapted for die and tool work, having adjustable toggle mechanism for moving one jaw relative to the other and including detachable accessories, such as, work gauge, punch and die, tool attaching and/or guiding means, etc.

United States Patent 1 1 Hildebrand 1 QUICKLY ADJUSTABLE VlSE JAw WITH TOOL COUPLE ELEMENTS [76] Inventor: Otto G. Hildebrand, 1907 Yucca,

Rio Rancho, N. Mex. 87124 [22] Filed: June 16, 1971 [21 Appl. No.: 153,529

[52] US. Cl. 269/87, 269/212 [51] Int. Cl .f. B25 b 1/14 [58] Field of Search 269/87, 87.1, 87.2,

314-- an 1 1 A [451 Sept. 18,1973

6/1950 Graether 269/212 9/1890 Sargent ..269/87.2

Primary Examiner-Harold D. Whitehead Assistant Examiner-James G. Smith Attorney-Watts, Hoffmann, Fisher & Heinke [57] ABSTRACT A multiple purpose workholder of the relatively movable jaw-type, especially adapted for die and tool work, having adjustable toggle mechanism for moving one jaw relative to the other and including detachable accessories, such as, work gauge, punch and die, tool attaching and/or guiding means, etc.

10 Claims, 11 Drawing Figures QUICKLY ADJUSTABLE VISE JAW WITH TOOL COUPLE ELEMENTS FIELD OF INVENTION The invention relates to workholders of the relatively movable jaw type having detachable accessories, such I as, tool attaching and/or guiding means.

PRIOR ART SUMMARY, OF INVENTION The present invention provides a novel and improved multi-purpose workholder of the relatively movable jaw-type, especially designed for use by die and tool makers, constructed for quick adjustment of the jaws relative to one another and for the attachment and detachment of accessories, such as, tools, tool holders and/or tool guides, work gauges, punches and dies, etc.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a workholder embodying the present in vention;

FIG. 2 is a side elevational view of the holder shown in FIG. 1;

FIG. 3 is a sectional view of the workholder shown in the preceding figures approximately on the line 3-3 of FIG. l 'with portions in elevation and with the slidable jaw in a different position;

FIG. 4 is an enlarged sectional view of the workholdershown in the preceding figures approximately on the line 4-4 of FIG. 2, with portions in elevation;

FIG. 5 is an enlarged fragmentary plan view of the workholder shown in FIGS. 1 to 4 having auxiliary tooling in the form of a punch, die and stripper detachably connected thereto;

FIG. 6 is a sectional view approximately on the line 6-6 of FIG. 5, with portions in elevation;

FIG. 7 is a fragmentary plan view of the workholder shown in FIGS. 1 to 4, having auxiliary tooling in the form of a work gauge and drill guidedetachably connected thereto;

FIG. 8 is ,a side elevational view of the apparatus shown in FIG. 7;

FIG. 9 is a fragmentary plan view similar to FIG. 7,

but showing a different type of drill guide attached to the workholder;

FIG. Us a fragmentary plan view of the workholder shown in FIGS. 1 to 4 having auxiliary tooling in the form of turning fixtures detachably secured thereto; and

FIG. l lis a sectionalview approximately on. line lI-ll of FIGS. 10.

DESCRIPTION OF PREFERRED EMBODIMENT The drawings shows a multi-purpose workholder of the relatively movable jaw-type, typically referred to as a vice, designated generally by the reference character A, and especially designed for use by die and tool makers. The work-holder comprises a member or assembly 8 having a fixed jaw C at one end, a movable jaw D slidable along spaced elongated planar surfaces on the member B for movement toand from the fixed jaw C, and quick acting toggle mechanism E for maniuplating the slidable jaw D. The fixed and movable jaws C, D, are constructed to detachably support accessories, such as, a punch F, stripper'G and die H, a work gauge K, drill guides L, M, a turning fixture or attachment, in cluding a bit holder and work guiide, N, P, respectively, etc. for locating and punching holes, drilling holes, turning work, etc.

The assembly B forms the base member of the preferred embodiment shown and comprises two longitudinal side rail members l0, 12 connected together in spaced relation at their right-hand ends, as viewed in the drawings, by an end member 14 secured to the ends of the side membersas by machine screws 16, 18. The

opposite or left-hand ends of the members l0, 12 are connected in spaced relation by the fixed jaw C, the partmember 20 of which is secured to the left-hand endsof the members 10, 12 as by machine screws 22,

24. The member 20 projects outwardly beyond planar surfaces 26, 28 of the members 10, 12.

The movable jaw Dof the preferred embodiment comprises a member 34, slidable along the planar side surfaces26, 28 of members l0, 12, a spacer member 36 projecting from the member 34 through the slot or space 38 between the side members 10, 12, and a guide member 40 at the projecting end of the spacer 36. The members 36 and 40 are secured to the member 34 by a countersunk head machine screw 42 threaded into a suitable tapped aperture in the member 34.

The sides of the rail members l0, 12 facing one another are stepped to provide three pair of surfaces 44, 46 and 48, 50 and 52, 54. The surfaces of each pair face one another and are progressively further apart in the direction away from the surfaces 26, 28 to provide pairs of planar surfaces 56, 58 and 60, 62 facing in the direction opposite the surfaces 26, 28 The pair of surfaces 44, 46 are spaced a distance such that the spacer member 36 is slidably received therebetween without undue clearance or play.

The, guide member 40 is movably located between the surfaces 52, 54 and the distance between the surfaces of the member 40 which slidably engage the planar surfaces 60, 62, and the side of the member 34 which slidably engages'the surfaces 26, 28 of the members 10, I2 is such that the movable jaw D is slidably supported upon the members 10 and 12 without undue clearance or play. In order to more securely maintain the parts 34, 36 and 40 in fixed relation to one another opposite ends of the spacer member 36 extend into suitable grooves 72, in the adjacent sides of the members 34, 40, respectively.

The slidable jaw D and the mechanism E for moving it towards the fixed jaw C are adapted to be adjustably positioned on the member B at different positions with respect to the fixed jaw C. For this purpose the mechanism, E, comprises an anchor R comprising a plunger supporting and guide member slidable upon the planar sides 26, 28 of the members 10, 12 and having a groove 82 in its side facing the member B within which a member 84 is fixedly connected by machine screws 86, 88 threaded into suitably tapped ends of an aperture 90 in the member 84. The member 84 extends through the slot 38 between the members 10, l2and has a pin 92 fixed in a transverse aperture in its projecting end. Opposite ends of the pin 92 project from opposite sides of the members 84.

Opposite ends of the pin 92 are adapted to be selectively engaged in aligned slots 100, 102 in rack or ratchet-like members 104, 106 at opposite sides of the member 84 and having teeth-like projections 107, 108 formed by the slots 100, 102. The members 104, 106 are detachably connected to the adjacent members 10, 12 by machine screws 110, 112, respectively. The sides of the members 10, 12 against which the members 102, 104 are secured are relieved for the length of the members where the slots 100, 102 occur so as not to interfere with the free movement of the pin 92 from one pair of slots to another. The slots 100, 102 open in the direction away from the planar surfaces 26, 28 and are inclined upwardly toward the end of the base B remote from the fixed jaw C. The pin 92 is adapted to be moved to any desired pair of aligned slots in the members 104, 106 to adjust the movable jaw D and the operating mechanism E therefor to any desired position along the member B by tilting the anchor R on the top side of the member B about the intersections of inclined surfaces 114 of the plunger guide member 80, formed by cutting away the lower left-hand corners of the member, with the surfaces thereof which engages the member B, until the pin 92 is clear of the members 104, l06and then moving the movable jaw D and its operating mechanism E along the member B to the desired position and thereafter engaging the pin 92 in the selected aligned slots 100, 102.

In addition to the anchor assembly R, the operating mechanism E includes an adjustable length plunger assembly S, including a member 120 slidably supported in a suitable aperture 122 in the member 80. The member 120 extends lengthwise of the member B of the workholder and its left-hand end abuts against a righthand surface 124 of a projection 126 of the movable jaw member 34. The opposite or right-hand end of the member 120 is suitably bored and tapped for the reception of one end of an adjusting double ended threaded member or screw 130. The opposite or right-hand end of the screw 130 is threaded into a suitablytapped aperture in a plunger head member 132 to which a lever 134 is pivotally connected by a pin 136. The plunger head member 132 has a flange part 138 extending to the right beyond the pivot pin 136 and provided with an adjustable stop screw 139 which limits rotation of the lever 134 in a clockwise direction about the pin 136.

Two links 140, 142 are pivotally connected to the lever 134 at opposite sides thereof by means of a pin 144 extending through suitable aligned apertures in the right-hand ends of the links 140, 142 and an aperture in the lever 134 spaced from the end of the lever pivotally connected by the pin 136 to the plunger head member 132. The opposite or left-hand ends of the links 140, 142 are pivotally connected to the member 80 of the anchor assembly R by the machine screws 86, 88, the shanks of which project through suitable apertures in the ends of the links 140, 142. In addition to the links 140, 142, links 150, 152 are connected by the machine screws 86, 88 to the anchor assembly R to the outside of the links 140, 142. The machine screws 86, 88 extend through elongated slots 154, 156 in the links 150, 152 thus permitting limited movement of the links 150, 152 relative to the anchor assembly R.

In the embodiment shown, each of the links 150, 152 comprise two parts at a slight angle to one another. The parts which have the slots 154, 156 therein normally extend generally parallel to the top side of the member B and the other parts are inclined upwardly at a slight angle and are pivotally connected by machine screws 160, 162 to opposite sides of the rearwardly projecting part 126 ofthe movable jaw member 34. The construction is such that as the anchor member R is moved lengthwise of the member B movement of the movable jaw D does not normally take place until the machine screws 86, 88 have engaged one end or the other of the slots 154, 156. The slots 154, 156 also facilitate tilting of the anchor assembly R about the top side of the member B to move the pin 92 from one pair of the slots 100, 102 to another, as previously described.

Provision is made for moving the movable jaw assembly D with the plunger assembly S when such movement is desired by the provision of a channel-shaped latch member 164 pivotally connected to the movable jaw assembly D by the machine screws 160, 162. The right-hand or outer free end of the latch member 164 is turned inwardly to provide a flange which can be selectively engaged in an annular groove 168 in the end of the member of the plunger assembly 8 adjacent to the movable jaw assembly. Typical face or wear plates 170, 172 are detachably connected to the facing sides of the members 20, 34 of the fixed and slidable jaw assemblies C, D, respectively.

As the lever 134 is rotated in a counter-clockwise direction from the position shown in FIGS. 1 to 3 of the drawings the pin 144 moves in. an arc about the pin 136 but the movement of the pin 144 lengthwise of the member B of the workholder is restricted by the links 140, 142 and the pivot pin 136 and the plunger S move toward the right. This does not produce any movement of the movable jaw assembly D unless the latch member 164 is engaged with the groove 168 in the member 120 but allows it to be moved by hand along the top side of the member B. Rotation of the lever 134 about the pin 136 in a clockwise direction projects the member 120 of the plunger assembly S through the anchor assembly R causing the movable jaw assembly D to move toward the fixed jaw assembly C and clamp on articles of suitable size therebetween. Any size article within the range of the workholder can be quickly secured or clamped between the fixed and slidable jaw assemblies by adjusting the anchor assembly R along the base B and subsequently manipulating the lever 134. Oscillation of the lever 134 conveniently moves the movable jaw assembly toward, and if the latch 164 is engaged in the groove 168 in the member 120 of the plunger assembly S, from the fixed jaw assembly.

As previously mentioned, the workholder A is constructed for the attachment of accessories and as shown in FIGS. 5 and 6 the workholder is provided with tools for punching holes in light metal. The tools referred to comprise the punch F, the stripper G and die H. The punch F comprises a shank received in an aperture 182 in the movable jaw D and located approximately in the center of the face of the jaw facing the stationary jaw C. The aperture extends lengthwise of the direction of movement of the jaw D. The tool end 184 of the punch F is of reduced diameter with reference to the diameter of the shank 180 and is adapted to be projected by movement of the jaw D through an aperture 186 in a part 188 of the stripper G and into an appropriate aperture 190 in the die H. The die is supported in an aperture 192 in the jaw C in line with the aperture 182 in the jaw D. The die and punch are retained in the members 20, 34, respectively, of the jaws C, D, by duplicate members 200, 202 in slots 204, 206 respectively, in the faces of the jaw members 20, 34, behind the face plates 170, 172. The members 200, 202 have bifurcated or forked ends which engage in sections 208, 210 of reduced diameter of the punch an die re spectively, thus detachably securing the latter in the fixed and movable jaw assemblies C, D, respectively.

The stripper G comprises, in addition to the member 188 having the aperture 186 therein and which member is supported on the member B of the workholder in a manner similar to that in which the member 34 of the slidable jaw D is supported thereto, a spacer member 212, and is adapted to be clamped to the member B by a clamp plate 214 engaging the space surfaces 60, 62 of the members 10, 12 and a machine screw 216 extending through the members 212, 214 and threaded into a tapped aperture in the member 188. The stripper G preferably abuts against the jaw C and for the purpose ofproviding space therebetween and the die H the member l88includes a base flange 218 along its fixed jaw side, the width of which can be made to provide any desired spacing between the stripper proper and the die H. The reference character W' indicates a work piece, in phantom, positioned to have a hole punched therein.

As shown in FIGS. 7 and 8, the workholder A is provided with a work gauge K and drill guide L. The work gauge I( comprises a bar 230 adjustably secured in aligned apertures 232, 234 in side flanges 236, 238 of the member projecting in the direction opposite the jaw D. The axis of the bar 230 extends transversely of the path of movement of the jaw D and is parallel with the plane of the planar surfaces 26, 28. Set screws 240, 242 threaded into a suitably tapped aperture in the flanges 236, 238 are provided for adjusting the bar 230 transversely. The bar 230 carries a plate-like member 244 provided with an aperture through which the bar extends and which may be adjusted lengthwise of the bar by a set screw 246 threaded into a suitably tapped aperture in the member 244. A projecting part of the member 244 carries an adjustable stop in the form of a threaded headed member 248 engaged in a tapped aperture 250 in the member 244 and provided with a lock nut 252 for securing the member 248 in an adjusted position. The member 244 can bepositioned so thata workpiece such as the piece W" shown in phantom can be abutted thereagainst.

The drill guide L comprises two elongated plate-like members 260, 262 having longitudinal slots 264, 266 in the central section thereof and apertures 270, 272 and 274, 276, respectively, in opposite ends. The members 260, 262 are adapted to be adjustably secured to a planar surface 278 of the member 20 of the jaw C by machine screws 280, 282 extending through the slots 264, 266, respectively, and into suitably tapped apertures 284, 286in a top flange 288 of the member 20 of the jaw C. A washer or spacer 290 interposed between the member 260 and the jaw C, the height of which is equal to the thickness of the member 264 permits the righthand end of the member 260,262, as viewed in FIGS. 7 and 8 to be overlapped and the apertures 274, 276 therein aligned for the reception of a guide bushing or member 292 having a suitable aperture 294 therein for guiding a drill such as the drill T shown in phantom in FIG. 8.

The drill guide M, shown in FIG. 9, is similar to that shown in FIGS. 7 and 8, and the duplicate parts are designated by the same reference characters. The only difference is the omission of the spacer 290 and the replacement of the guide bushing 292 with a guide plate 300 having a plurality of drilled guide apertures 302, six in the embodiment shown, of different size. The plate 300 is connected, to the ends of the members 260, 262 other than the ends to which the guide member 292 was connected, by machine screws 304, 306 extending through suitable apertures in the member 300 and threaded into the tapped apertures 270, 272, previously referred to in the members 260, 262.

The member 34 of the movable jaw assembly D has two spaced top flanges 310, 312 extending in the direction away from the fixed jaw assembly C provided with tapped apertures 314, 316 similar to the tapped apertures 284, 286 in the member 20 of the fixed jaw assembly C for connecting the drill guides L, M to the movable jaw assembly D in place of the fixed jaw as sembly, as desired.

The workholder A shown in FIGS. 10 and 11, is provided with turning tooling, designated generally by the reference character N, and the drill guide apparatus, shown in FIG. 7 and 8 is employed for guiding the work W, shown in phantom, in its movement past a turning tool or bit 320. The work W' is carried by the spindle head V of a drill press and can be fed thereby past the turning tool or bit 320 either manually or. automatically depending upon the drill press employed.

The turning tool or bit 320 is adjustably fixed in a holder 322 slidably supported in a groove 324 in a member 326 slidably supported on pins 328, 330 fixed to a plate 332. The member 326 and the plate 332 are adapted to be clamped together between the fixed and movable jaw assemblies C, D of the workholder. When the pressure of the jaws of the workholder on the members 326, 332 is released compression springs 334, 336 located in apertures 340, 342 in the member 326, release the pressure between the members 326, 332 which pressure is utilized to clamp the toolholder 322 in adjusted position in the member 326. The toolholder 322 is adjusted or moved lengthwise of the slot 324 in the member 326 within which it is slidably supported by a headed screw 344 threaded into a suitable tapped aperture 346 in the member 326. The head 348 of the screw 344 is fixed against longitudinal movement relative to the member 322 by being positioned between two spaced flanges 350, 352 of the member 322. The turning tool or bit 320 is moved or adjusted relative to the member326 by rotating the screw 344 so as to proj ect a suitable distance into an aperture 354 in the member 326 in line with the guide aperture 294 in the guide bushing 292 which, as previously indicated, in this instance serves as a work guide as distinguished from a drill or tool guide. I t

From the foregoing description of the preferred embodiment of the invention it will be apparent that the objects and advantages heretofore enumerated and others have been accomplished and that there has been provided a new and improved workholder of the relatively movable jaw-type, particularly adapted for die and tool work which can be readily manipulated and have different types of supplemental tooling as a part thereof.

- While the preferred embodiment has been described in considerable detail it will be apparent that the invention is not limited to the construction shown and it is the intention to hereby cover all adaptations, modifications and uses thereof which come within the practice of those skilled in the art to which the invention relates and-the scope of the appended claims.

I claim:

1. A workholder of the relatively movable jaw-type comprising: a member having an elongated planar surface on one side and teeth-like projections extending in the direction of the opposite side; a first jaw adjacent to one end of said member projecting outwardly of said planar surface in a direction normal thereto; a second jaw slidable lengthwise of said planar surface; an anchor member slidable on said planar surface at the side of said second jaw opposite said first jaw and having a part extending inwardly of said planar surface; an abutment on said part of said anchor member selectively engageable in the spaces between said projections; a plunger slidably supported by said anchor member for movement lengthwise of said planar surface and engageable at one end with said second jaw; a lever pivotally connected to said plunger adjacent to its end opposite said one end; a first link having one end pivotally connected to said anchor member and its other'end pivotally connected to said lever at a point spaced from the pivotal connection of said lever with said plunger; a second link having one end pivotally connected to said movable jaw; and means connecting the end of said second link opposite said one end to said anchor member for both pivotal movement and limited movement lengthwise of said planar surface. 16

2. A workholder as claimed in claim 1 having a member selectively connectable between said second jaw and said plunger.

3. A workholder as claimed in claim 1 having means for limiting rotation of said lever about its pivotal connection with said plunger.

4. A workholder as claimed in claim 1 in which said first link together with said anchor and lever and the pivotal connections of said first link with said anchor and said lever and said lever with said plunger constitute toggle linkage, and means limiting rotation of said lever about its pivotal connection with said plunger such that its pivotal connection with said first link is in a slightly overcenter position with respect to the pivotal connection of said link with said anchor and said lever with said plunger.

5. A workholder as claimed in claim 1 in which at least one of said jaw members has an aperture extending lengthwise of said planar surface for the attachment of tooling such as punches and/or dies.

6. A workholder as claimed in claim 1 in which at least one of said jaw members has a planar surface parallel with said planar surface along which said second jaw is movable with an aperture therein suitable for the attachment of tooling such as a drill guide.

7. A workholder as claimed in claim 1 having an aperture in said first jaw extending in a direction transverse to the length of said planar surface along which said second jaw is movable but parallel with said planar surface suitable for the attachment of a work gauge.

8. A workholder as claimed in claim 1 in which at least one of said jaws has an aperture extending length wise of said planar surface along which said second jaw is movable suitable for the attachment of tooling, such as, punches and/or dies; at least one of said jaws having an outer surface parallel with said planar surface and having an aperture therein normal to said planar surface suitable for the attachment of tooling, such as, drill and/or work guides; and said first jaw having an aperture extending in a direction transverse to the length of said planar surface but parallel with said planar surface suitable for the attachment of a work gauge.

9. A workholder of the relatively movable jaw-type comprising: a member having an elongated slot therein and spaced planar surfaces on one side at opposite sides of the slot and teeth-like porjections extending in the direction opposite to said one side and at opposite sides of the slot; a first jaw at one end of said member projecting outwardly of said planar surfaces in the direction normal thereto; a second jaw slidable on said planar surfaces; an anchor member slidable on said planar surfaces at the side of said second jaw opposite said first jaw and having an extension projecting into said slot in said members; abutment means on said extension of said anchor member selectively engageable in the spaces between said projections; a plunger of adjustable length slidably supported by said anchor member for movement lengthwise of said planar surfaces and engageable with said second jaw; means for selectively connecting said plunger to said second jaw; a lever pivotally connected to said plunger; a first pair of links having their one ends pivotally connected to opposite sides of said anchor member and their other ends pivotally connected to opposite sides of said lever at a point spaced from the pivotal connection of said lever with said plunger; a second pair of links having their one ends pivotally connected to said movable jaw; and means connecting the other ends of said second pair of links to opposite sides of said anchor member for both pivotal movement and limited movement lengthwise of said planar surface.

10. A workholder as claimed in claim 9 in which said first pair of links together with said anchor member and lever and their pivotal connections with said anchor member and said lever, and said lever with said plunger constitute toggle linkage, and means limiting rotation of said lever about its pivotal connection with said plunger such that its pivotal connection with said first pair of links is in a slightly overcenter position with respect to the pivotal connection of said first pair of links with said anchor member and said lever with said plunger.

* i t i 

1. A workholder of the relatively movable jaw-type comprising: a member having an elongated planar surface on one side and teethlike projections extending in the direction of the opposite side; a first jaw adjacent to one end of said member projecting outwardly of said planar surface in a direction normal thereto; a second jaw slidable lengthwise of said planar surface; an anchor member slidable on said planar surface at the side of said second jaw opposite said first jaw and having a part extending inwardly of said planar surface; an abutment on said part of said anchor member selectively engageable in the spaces between said projections; a plunger slidably supported by said anchor member for movement lengthwise of said planar surface and engageable at one end with said second jaw; a lever pivotally connected to said plunger adjacent to its end opposite said one end; a first link having one end pivotally connected to said anchor member and its other end pivotally connected to said lever at a point spaced from the pivotal connection of said lever with said plunger; a second link having one end pivotally connected to said movable jaw; and means connecting the end of said second link opposite said one end to said anchor member for both pivotal movement and limited movement lengthwise of said planar surface. 16
 2. A workholder as claimed in claim 1 having a member selectively connectable between said second jaw and said plunger.
 3. A workholder as claimed in claim 1 having means for limiting rotation of said lever about its pivotal connection with said plunger.
 4. A workholder as claimed in claim 1 in which said first link together with said anchor and lever and the pivotal connections of said first link with said anchor and said lever and said lever with said plunger constitute toggle linkage, and means limiting rotation of said lever about its pivotal connection with said plunger such that its pivotal connection with said first link is in a slightly overcenter position with respect to the pivotal connection of said link with said anchor and said lever with said plunger.
 5. A workholder as claimed in claim 1 in which at least one of said jaw members has an aperture extending lengthwise of said planar surface for the attachment of tooling such as punches and/or dies.
 6. A workholder as claimed in claim 1 in which at least one of said jaw members has a planar surface parallel with said planar surface along which said second jaw is movable with an aperture therein suitable for the attachment of tooling such as a drill guide.
 7. A workholder as claimEd in claim 1 having an aperture in said first jaw extending in a direction transverse to the length of said planar surface along which said second jaw is movable but parallel with said planar surface suitable for the attachment of a work gauge.
 8. A workholder as claimed in claim 1 in which at least one of said jaws has an aperture extending lengthwise of said planar surface along which said second jaw is movable suitable for the attachment of tooling, such as, punches and/or dies; at least one of said jaws having an outer surface parallel with said planar surface and having an aperture therein normal to said planar surface suitable for the attachment of tooling, such as, drill and/or work guides; and said first jaw having an aperture extending in a direction transverse to the length of said planar surface but parallel with said planar surface suitable for the attachment of a work gauge.
 9. A workholder of the relatively movable jaw-type comprising: a member having an elongated slot therein and spaced planar surfaces on one side at opposite sides of the slot and teeth-like porjections extending in the direction opposite to said one side and at opposite sides of the slot; a first jaw at one end of said member projecting outwardly of said planar surfaces in the direction normal thereto; a second jaw slidable on said planar surfaces; an anchor member slidable on said planar surfaces at the side of said second jaw opposite said first jaw and having an extension projecting into said slot in said members; abutment means on said extension of said anchor member selectively engageable in the spaces between said projections; a plunger of adjustable length slidably supported by said anchor member for movement lengthwise of said planar surfaces and engageable with said second jaw; means for selectively connecting said plunger to said second jaw; a lever pivotally connected to said plunger; a first pair of links having their one ends pivotally connected to opposite sides of said anchor member and their other ends pivotally connected to opposite sides of said lever at a point spaced from the pivotal connection of said lever with said plunger; a second pair of links having their one ends pivotally connected to said movable jaw; and means connecting the other ends of said second pair of links to opposite sides of said anchor member for both pivotal movement and limited movement lengthwise of said planar surface.
 10. A workholder as claimed in claim 9 in which said first pair of links together with said anchor member and lever and their pivotal connections with said anchor member and said lever, and said lever with said plunger constitute toggle linkage, and means limiting rotation of said lever about its pivotal connection with said plunger such that its pivotal connection with said first pair of links is in a slightly overcenter position with respect to the pivotal connection of said first pair of links with said anchor member and said lever with said plunger. 